The present invention relates to a new and improved container and method of forming the container. The container includes a liner around which flexible material is wound.
Filament wound plastic pressure vessels have previously been formed by winding strands or roving of fibers, particularly continuous glass fibers, around a blow-molded or rotationally cast thermoplastic liner or a laid-up thermoset liner. During winding of the liner with the filament, the liner may be supported by a winding pole. The liner is formed with holes at opposite ends of the liner. The winding pole is inserted through the holes at opposite ends of the liner. The liner is connected with the winding pole. The winding pole and liner are rotated together during winding of filament around the liner.
In addition, filament wound vessels have previously been formed by inserting drive lugs into holes in opposite ends of a liner. Torque is transmitted through the drive lugs to the liner to rotate the liner during the winding of filaments around the liner.
These methods of forming a filament wound pressure vessel require the making of holes in opposite ends of the liner. When the apparatus utilized to support and rotate the liner during winding of the filament around the liner is removed from the liner, the holes must either be patched or fitted with bulkhead fittings in order to provide a pressure tight seal. However, there is a potential source of leakage at the locations where the liners are patched or closed with bulkhead fittings. In addition, patching or closing the holes at opposite ends of the liner increases the cost of making the filament wound vessel.
In accordance with one of the features of the present invention, the prior art problem of sealing openings formed in a liner to enable the liner to be rotated during winding of filament around the liner is eliminated. This is accomplished by eliminating the formation of openings in the liner to accommodate apparatus to rotate the liner during winding of the filament. Therefore, filament wound containers constructed in accordance with the present invention have very few or no leakage problems.
In accordance with the present invention, during forming of a container, plates are attached to opposite end portions of a liner with adhesive. The liner surfaces to which the plates may be attached are free of through openings to the interior of the liner. The liner is supported for rotation about an axis which extends through the plates at opposite ends of the liner. The liner is rotated under the influence of torque which is transmitted to the liner through at least one of the plates and adhesive attaching the one plate to the liner.
During rotation of the liner, flexible material is wound around the liner. The flexible material is wound over the plates at the opposite ends of the liner. Covers are advantageously connected with the plates to cover the areas where the liner was supported during winding of the flexible material around the liner.